Many communication systems exchange data using an isolator circuit, such as a transformer. For example, in an Ethernet communication system, the IEEE 802.3 (e.g., Institute of Electrical and Electronics Engineers 802.3-2012) standard specifies that electrical isolation be provided between an Ethernet physical layer circuit—usually referred to as an “Ethernet PHY”—and an Ethernet port (e.g., a medium-dependent interface (MDI)), which provides a physical and electrical connection to a cabling medium (e.g., ANSI/TIA-568-C.0, Generic Telecommunications Cabling for Customer Premises, Category 5)). In such Ethernet implementations, data may be transmitted from an Ethernet-enabled device onto the cabling medium using a transformer.
However, using a transformer to transmit data between isolated systems or subsystems may be associated with certain drawbacks. For example, baseline wander may occur, when voltage driven on the transformer droops over time as energy leaks out of the transformer due to its inductive nature in conjunction with other impedances to which it is coupled. Applications and standards may require limiting such baseline wander.
Prior approaches to limiting baseline wander include using a transformer having an inductance value that either complicates or precludes use of an integrated transformer circuit. For example, some Ethernet standards may translate to use of a transformer inductance of at least 80 microHenry (μH) or more, such as even 350 μH or more.